engleski

Preliminary screening of wood biomass ashes for partial resources replacements in cementitious materials

WWorldwide there is significant increase the amount of wood biomass ash (WBA) as a waste during the process of wood biomass combustion. Moistly WBA is landfilled. As a potential green solutions to prevent waste generation and promote the use of waste as a resource, this paper is focused on WBA characterization for its further possible use in the cement and concrete industry. In this study, 21 different sources of WBA, namely fly ash, bottom ash, and mixed ash from 10 different power plants in the Republic of Croatia were detail characterized based on their chemical composition, particle-size distribution, particle morphology, heavy-metal content and mineralogical composition. Compared to the criteria listed for the use of coal fly ash in the concrete industry (EN 450), most WBAs exhibit higher loss of ignition (LOI) values, high CaO and MgO contents, and higher total alkali and sulfur content. The results show a higher amount of alkalies and heavy metals in wood fly biomass ash (WBA-F) as compared to wood bottom biomass ash (WBA-B), but also their potential stabilisation in glassy phases. This results indicates the need for volume stability and alkali-aggregate testing of cement composites with WBA content. The particle size of WBA-B is much larger than that of WBA-F, owing to which WBA-B can potentially replace aggregates in cement composites. Based on WBA characterization results, collected WBAs were benchmarked and categorised for the different resource replacements in production of cement and concrete: 1) partial replacement of a raw meal for clinker production ; 2) partial cement replacement as a mineral admixture in cementitious composites, and 3) partial replacement of aggregates used for concrete production. The proposed preliminary ranging of WBAs will serve as a base for further experimental testing in order to define the influence of individual WBA on the cement composite´s behaviour through mechanical and durability properties.

Wood biomass ash ; Cement-based materials ; Cement partial replacement ; Aggregate partial replacement ; Quality ranking

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